Accuracy of spectral entropy as an electroencephalographic measure of level of sedation during general anesthesia / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the accuracy of spectral entropy including response entropy(RE)and state entropy(SE)as a new electroencephalographic measure of depth of sedation during general anesthesia.Methods Twenty ASA Ⅰ or Ⅱ patients aged 20-55 yr undergoing elective abdominal surgery were studied.Anesthesia Was induced with intravenous propofol,fentanyl and vecuronium.After tracheal intubation anesthesia was maintained with sevoflurane inhalation and intermittent iv boluses of fentanyl and vecuronium.BP,HR,SpO2,spectral entropy(Datex-Ohmeda)and BIS(Aspect Medical)were monitored during anesthesia.Loss of eyelash reflex and unresponsiveness to verbal stimulus and mild prodding and shaking were considered to be signs of loss of consciousness(LOC).The time of regaining consciousness Was defined as the time when patients started responding to verbal commands.RE,SE and BIS were recorded before anesthesia(baseline),10 min before LOC,immediately after LOC,immediately after tracbeal intubation,1 h after skin incision,10 min before regaining consciousness immediately after consciousness was regained and 10 min after extubation.Results There were sisnificant changes in RE,SE and BIS during the transition from consciousness to LOC.The RE,SE and BIS values for LOC were 76,73 and 68 with sensitivity of 94%,95%and 92%and specificity of 92%,94%and 91%respectively.The accuracy of RE.SE and BIS in predicting LOC was 93%,95%and 94%respectively.The RE,SE and BIS values for regaining consciousness were 82,75 and 70 with sensitivity of 95%,95%and 91%and specificity of 93%,96%and 93%respectively.The accuracy in predicting regaining of consciousness was 98%,96%and 97%respectively.Conclusion Entropy index Can accurately monitor level of sedation during general anesthesia.